This invention relates to ammonium polyamidoamines and to their use in the manufacture of paper.
As disclosed in U.S. Pat. No. 3,445,441, polyamidoamines are useful as demulsifiers, corrosion inhibitors, and flocculants for the clarification of water. These polyamidoamines are normally produced by reacting nearly stoichiometric amounts of an alkyl acrylate with a polyamine such as polyalkylene polyamine. Unfortunately, such polymers, which are not curable, often do not have sufficient molecular weight to be useful in many applications requiring viscosity enhancement and/or high flocculant capability.
U.S. Pat. No. 3,305,493 discloses the use of thermosetting adducts of the polyamidoamines and epichlorohydrin in the sizing of paper. Although such thermosetting adducts, after increase in molecular weight through cross-linking, have sufficient molecular weight to be useful in many applications, it is difficult to control the cross-linking reaction so that the formation of unwanted gels is prevented. On the other hand, if the cross-linking reaction is stopped prematurely, the resulting product does not exhibit the desired activity.
In view of the foregoing deficiencies of the conventional polyamidoamines, it is highly desirable to provide a polymer that has reproducible characteristics and has sufficient activity to be useful in applications such as wet strength additives in the manufacture of paper and the like.